A lot of us beg the question; 'How do Disney age their lions in The Lion King' or 'How should we measure a TLK lion's life; in human terms or lion?' A lot of us ask this question so we can use it in fanfictions, and it's fairly easy to find the answer.

First, let's look at the popular song, 'Be Prepared':

"So prepare for the coup of the century (Oooh!)

Be prepared for the murkiest scam (Oooh... La! La! La!)

Meticulous planning (We'll have food!)

Tenacity spanning (Lots of food)

Decades of denial (We repeat)

Is simply why I'll..."

Let's look at that line: 'decades of denial.' Lions rarely make it past their second decade, and Scar already seems like a mature, perhaps even near mid-age lion. So maybe we should expect something like a human lifespan for our TLK lions?

Another point to consider is the TLK Mouseworks book. The book says that Simba was in self-exile in the jungle for many years. Simba is still a youth when he returns to the Pridelands, but lions in real life are fully mature at around 5 years. So it's been proven that TLK lions do not age on a realistic level.

So yeah, that's that.